The Importance of Vegetation
Vegetation is one of the most important parts of sand dunes. Vegetation stabilises sand dunes as well as helping to maintain it shape. Vegetation also helps to prevent erosion by binding it together. Dunes are fragile and cannot be walked upon. Boardwalks have been built in order to prevent erosion and ensure stability. Long Reef Beach has lots of vegetation such as the Spinifex, which is a type of grass. Collaroy beach has limited amounts of vegetation because houses are built on the sand dunes. This has increased the amount of erosion on this beach.
The Formation of Sand Dunes A sand dune is an accumulation of sand, which is natures way of protecting the land behind from coastal processes being aeolian such as wind and hydrospheric such as water. There are many ways sand dunes are formed. The three oceanic processes are: cumulative; deposition of sand onto the beach, building it up; destructive, carry sand away, eroding the beach; and longshore drifts carry sand from one specific area of a beach to another meaning it builds one area and destroys another. Another process is from the wind; it carries the sand to the coastline to encourage dune formation. The stronger winds destroy the dune by carrying particles away, eroding the sand and land. Vegetation, such as spinifex grass help the formation of dunes, it does this by trapping the sand in its roots, holding the sand together. If dunes didn't exist, or are destroyed by human development, land would be eroded instead of the sand, causing buildings to collapse.
Impact of Human Action
Human activity has a significant impact on the condition of sand dunes and effectiveness of the purpose of sand dunes. Different areas of the dunes have different stability levels. For exaple the foredune, which is located approximately 100m from the shorline, cannot withstand human activity such as walking, cycling etc. The foredune is the most fragile part of the shore.
Human actions can have both positive and negative effects on sandunes. A positive impact revolves around vegetation. When human's plant vegetation they prevent erosion of the dunes. The plants can withhold the extreme weather conditions of the beach. Vegetation supports the sand dunes and holds sand into the ground.
Human's actions can negatively impact sand dunes by ripping out vegetation when walking on it. Human access is often restricted around specific areas to allow dune vegetation to regenerate and prosper. Coastal landforms
All Coastal landforms are made from geological processes such as wind, salt spray and waves. Some landforms are lagoons, dunes, beaches and headlands. The beach Collaroy lacks landforms such as lagoons and sand dunes due to the overdevelopment of the beaches shoreline. Further along the coast Dee Why and Long Reef beach has a lagoon, natural dunes and headlands because it is protected from development. These landforms were caused by erosion and deposition.
For example Dee Why lagoon was formed when the longshore drift from Collaroy and Long Reef beaches moved the sand along the coast and deposited it on the beach, closing off the mouth of the river and turning it into a separate body of water. Human interactions with this lagoon could cause a large loss of sand if the lagoon were to overflow or move as a result. The coastal landforms are vital in protecting the land and in cases such as Narrabeen they are vital in protecting the buildings and homes of local residents.
Impact of Natural Disasters
Natural disasters such as storms affect Australian beaches every year. Storms have the ability to remove large amounts of sand from the dunes with the replacement of that sand extending to a longer period of time. Storms also cause the foredune to recede which is a reason why development on foredunes should be restricted. Terrigal beach suffered from storms between 1967 and 1974. The loss of sand was caused by several weeks of destructive waves followed by high spring tides.
Examples of the danger natural disasters cause is the repeated ravishment of Collaroy beach. Time and time again, the beach has had its shores wasted away, up to the point where properties along the shoreline are having their foundations eroded out from underneath them. Protection strategies put in place such as the dropping of rocks in the Collaroy beach active zone has only proved to enhance the effects of these storms.
Sand Nourishment
Management Plan
To prevent and reduce erosion at Collaroy/Narrabeen, a management plan is required. There are several management strategies included in the 1997 Collaroy/ Narrabeen coastal management plan. The plan must suit the needs/desires of all affected parties in Collaroy (Government, council, stakeholders).
The strategies employed include:
· The buy back scheme which means that before a high risk property is placed on the market the council has the right to decide whether or not it wants to buy the property. The property is then demolished, reducing pressure on the dunes. This scheme is extremely costly to the council as it is a long-term solution to the issue.
· A new 1km seawall was proposed for Collaroy beach in order to protect housing and the dunes. Unfortunately this scheme did not get passed by council as stakeholders protested by saying it would damage the beach, look ugly, make access difficult and be costly for tax payers.
· One current on going scheme is the technological monitoring of the beach. This involves coastal imaging cameras being mounted on the flight deck and surf lifesaving club roof in order to allow the council to become aware of changes in the environment that may impact Collaroy beach. JJ
The Importance of Vegetation
Vegetation is one of the most important parts of sand dunes. Vegetation stabilises sand dunes as well as helping to maintain it shape. Vegetation also helps to prevent erosion by binding it together. Dunes are fragile and cannot be walked upon. Boardwalks have been built in order to prevent erosion and ensure stability. Long Reef Beach has lots of vegetation such as the Spinifex, which is a type of grass. Collaroy beach has limited amounts of vegetation because houses are built on the sand dunes. This has increased the amount of erosion on this beach.
The Formation of Sand Dunes
A sand dune is an accumulation of sand, which is natures way of protecting the land behind from coastal processes being aeolian such as wind and hydrospheric such as water. There are many ways sand dunes are formed. The three oceanic processes are: cumulative; deposition of sand onto the beach, building it up; destructive, carry sand away, eroding the beach; and longshore drifts carry sand from one specific area of a beach to another meaning it builds one area and destroys another. Another process is from the wind; it carries the sand to the coastline to encourage dune formation. The stronger winds destroy the dune by carrying particles away, eroding the sand and land. Vegetation, such as spinifex grass help the formation of dunes, it does this by trapping the sand in its roots, holding the sand together. If dunes didn't exist, or are destroyed by human development, land would be eroded instead of the sand, causing buildings to collapse.
Impact of Human Action
Human activity has a significant impact on the condition of sand dunes and effectiveness of the purpose of sand dunes. Different areas of the dunes have different stability levels. For exaple the foredune, which is located approximately 100m from the shorline, cannot withstand human activity such as walking, cycling etc. The foredune is the most fragile part of the shore.
Human actions can have both positive and negative effects on sandunes. A positive impact revolves around vegetation. When human's plant vegetation they prevent erosion of the dunes. The plants can withhold the extreme weather conditions of the beach. Vegetation supports the sand dunes and holds sand into the ground.
Human's actions can negatively impact sand dunes by ripping out vegetation when walking on it. Human access is often restricted around specific areas to allow dune vegetation to regenerate and prosper.
Coastal landforms
All Coastal landforms are made from geological processes such as wind, salt spray and waves. Some landforms are lagoons, dunes, beaches and headlands. The beach Collaroy lacks landforms such as lagoons and sand dunes due to the overdevelopment of the beaches shoreline. Further along the coast Dee Why and Long Reef beach has a lagoon, natural dunes and headlands because it is protected from development. These landforms were caused by erosion and deposition.
For example Dee Why lagoon was formed when the longshore drift from Collaroy and Long Reef beaches moved the sand along the coast and deposited it on the beach, closing off the mouth of the river and turning it into a separate body of water. Human interactions with this lagoon could cause a large loss of sand if the lagoon were to overflow or move as a result. The coastal landforms are vital in protecting the land and in cases such as Narrabeen they are vital in protecting the buildings and homes of local residents.
Impact of Natural Disasters
Natural disasters such as storms affect Australian beaches every year. Storms have the ability to remove large amounts of sand from the dunes with the replacement of that sand extending to a longer period of time. Storms also cause the foredune to recede which is a reason why development on foredunes should be restricted. Terrigal beach suffered from storms between 1967 and 1974. The loss of sand was caused by several weeks of destructive waves followed by high spring tides.
Examples of the danger natural disasters cause is the repeated ravishment of Collaroy beach. Time and time again, the beach has had its shores wasted away, up to the point where properties along the shoreline are having their foundations eroded out from underneath them. Protection strategies put in place such as the dropping of rocks in the Collaroy beach active zone has only proved to enhance the effects of these storms.
Sand Nourishment
Management Plan
To prevent and reduce erosion at Collaroy/Narrabeen, a management plan is required. There are several management strategies included in the 1997 Collaroy/ Narrabeen coastal management plan. The plan must suit the needs/desires of all affected parties in Collaroy (Government, council, stakeholders).
The strategies employed include:
· The buy back scheme which means that before a high risk property is placed on the market the council has the right to decide whether or not it wants to buy the property. The property is then demolished, reducing pressure on the dunes. This scheme is extremely costly to the council as it is a long-term solution to the issue.
· A new 1km seawall was proposed for Collaroy beach in order to protect housing and the dunes. Unfortunately this scheme did not get passed by council as stakeholders protested by saying it would damage the beach, look ugly, make access difficult and be costly for tax payers.
· One current on going scheme is the technological monitoring of the beach. This involves coastal imaging cameras being mounted on the flight deck and surf lifesaving club roof in order to allow the council to become aware of changes in the environment that may impact Collaroy beach. JJ
Concluding statement